Currently, apparatuses for determining thickness of a dynamic or static stream of films are available (e.g., see Patent Document 1 listed below). The apparatuses disclosed in Patent Document 1 is, as shown in FIG. 16, comprised of a main frame 100, a sheet-thickness gauge sensor 102, a measuring head 103, and a movable mechanism 104. A reference symbol ‘a’ denotes any of measured objects shaped in sheet.
The main frame 100 is configured to be a frame that permits a sheet(s) a to pass through. The sheet-thickness gauge sensor 102 may be any of those which are capable of emitting electro-magnetic waves, or radioactive or particle rays as well as pneumatic, capacitance-operated, ultrasonic, non-contact or contact gauges, and Patent Document 1 discloses a gauge of pneumatic sensing. In the disclosure, a pair of the sheet-thickness gauge sensors 102 are located respectively over and under the sheet a; i.e., orthognal opposed to each other. Each of the pair of the sheet-thickness gauge sensors 102 is supported at a distal end of the measuring head 103, facing or pointing toward the sheet a by any suitable means such as an air cylinder (not shown) that serves as a reciprocating carriage and allows the head and thus the sensor to come close to and recede from the sheet a. The movable mechanism 104 causes the measuring head 103 to move in lateral directions perpendicular to the passage of the sheet a. Also, a pair of the movable mechanisms 104 are located over and under the passage of the sheet(s) a, opposed to each other within the main frame 100.
Assuming that X-rays are emitted to determine thickness of the sheet a in such a thickness gauge apparatus, the pair of the sheet-thickness gauge sensors 102 are cooperative X-ray emitter and detector in the vertically opposite locations over and under the sheet a, respectively. Specifically, X-rays radiated from the X-ray emitter are directed to the bottom side of the sheet a and then vertically transmitted through the entire thickness of the same, and eventually received at the X-ray detector. The X-rays thus received by the X-ray detector is quantified to determine the thickness of the sheet a.